1. Field of the Invention
The present invention relates to thermal printers which use ultrasonic energy to fuse dye into a receiver.
2. Description of the Prior Art
Currently, thermal dye transfer is usually followed by fusing to further "set" the dye into the receiver layer and immobolize it in the mordant. The term thermal dye transfer refers to all methods of transferring dye by thermal methods irregardless whether the thermal energy is directly or indirectly generated and/or delivered, such as, but not inclusively, resistive head, resistive ribbon, laser and ultrasonic thermal dye transfer. There are two technologies available for fusing; thermal and solvent fusing. The former, which is most often used consists of reheating the receiver after thermal dye transfer. Because this technique uses thermal energy and generates a large amount of heat, generally a separate unit, isolated from the heat sensitive donor, is required to perform this operation. This then requires a distinct two step process and two units, one for image transfer and one for fusing, which in turn increases time and cost of thermal imaging.
Another technique consists of exposing the image to solvent vapors after thermal dye transfer. This technique has several drawbacks which include fire hazard, toxicity and ventilation requirements of working with solvent vapors.